Safety Pressure Cap

ABSTRACT

A safety radiator cap has a centrally located pressure plunger that forces pins outward against the inside of a radiator fill tube to prevent opening of the cap when the system is under pressure. As the liquid cools, the pressure is reduced and the pins retract due to biasing springs which allow the cap to be removed thus ensuring that the cap can only be removed when safe. Pressure pads at the end of the pins allow an embodiment of the invention to be used in any vehicle without retrofitting.

RELATED APPLICATIONS

This application claims priority and herein incorporates by reference U.S. provisional patent application 60/885,553, filed Jan. 18, 2007.

BACKGROUND OF THE INVENTION

The internal combustion engine has revolutionized the world we live in. Although some engines use air cooling techniques to control the temperature, most vehicles use liquid cooled systems that utilize a radiator filled with a liquid that circulates through a series of hoses and channels in the engine block designed to transfer heat away from the engine. There are basically two types of water cooling systems. The older system utilizes a non-pressurized radiator that operates at a temperature of approximately 180° F. The hot water from the engine is pumped through the radiator while airflow keeps the operating temperature constant. This means that while the system is operating properly, the water is kept below the boiling point, and therefore the radiator cap of such a system can be opened without significant risk of injury. Of course, even with this system, overheating can result in serious injury when trying to remove the radiator cap.

Because of the thermodynamic advantage associated with greater temperature differences, most current liquid cooled systems operate with a pressurized radiator, allowing the coolant to remain a liquid above the atmospheric boiling point. Because of this, even in a properly operating system, it is extremely dangerous to remove the radiator cap until the coolant is been given sufficient time to cool down. In such systems, if the radiator cap is removed before cooling, the liquid will instantly vaporize in a dangerous explosion of steam. There is a need for a radiator cap that keeps a user from being injured when trying to access the cooling system of the vehicle.

SUMMARY OF THE INVENTION

A safety radiator cap has a centrally located pressure plunger that forces pins outward against the inside of a radiator fill tube to prevent opening of the cap when the system is under pressure. As the liquid cools, the pressure is reduced and the pins retract due to biasing springs which allow the cap to be removed thus ensuring that the cap can only be removed when safe. Pressure pads at the end of the pins allow an embodiment of the invention to be used in any vehicle without retrofitting.

Other features and advantages of the instant invention will become apparent from the following description of the invention which refers to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cutaway view of an embodiment according to the present invention.

FIG. 2 is a cutaway view of the embodiment shown in FIG. 1 showing the safety pins engaged.

FIG. 3 is a cutaway view of the embodiment according to the present invention showing the safety pin engaged with a specialized radiator fill tube.

FIG. 4 is a perspective view of a radiator fill tube according to the present invention.

FIG. 5 is a perspective view of the safety radiator cap engaged according to the present invention.

FIG. 6 is a close up view of a section shown in FIG. 5.

FIG. 7 is a cutaway view of another embodiment according to the present invention.

FIG. 8 is a cutaway view of the embodiment shown in FIG. 7 with safety pins engaged.

FIG. 9 is a perspective view of a safety radiator cap according to the embodiment shown in FIG. 8.

DETAILED DESCRIPTION OF THE INVENTION

Reference is now made to the drawings in which reference numerals refer to like elements.

Referring now FIGS. 1 through 4, a safety radiator cap 100 has a center slide 126 along which a pressure plunger 134 moves up and down in response to the pressure within a radiator (not shown). In the embodiment shown, at least two pins 118 are radially disposed within a channel in lower ring 122, which guides pin 118 as it moves back and forth in response to pressure. At another end of pin 118 is a distally disposed pin follower 116, which rides along an angled section of pressure plunger 134. Disposed along a bottom portion of pressure plunger 134 is pressure plate 136.

Safety radiator cap 100 has a Portion 106 is held in place by a end holder 104 which is welded, bolted or glued to maintain integrity. An upper ring 102 applies pressure to an upper gasket 108 which is spring-loaded connection with outer spring 110. As safety radiator 100 is pushed down on upper sealing seat 144 upper gasket 108 seals the cooling system accessible through radiator fill tube 140 by pushing against upper sealing ring 154 of radiator fill tube 140. Safety radiator cap 100 is locked in place by locking tabs 158 fitting within locking cutouts 146 as is known in the art. In this embodiment, as soon as pressure begins to build within the cooling system, pressure plate 136 moves upward along center slide 126 overcoming center spring 114 which biases pressure plunger 14 in a non-locked position. Pressure plunger 134 has a sloped portion where pin followers 116 ride up and down causing them to move laterally in response to the pressure change within the cooling system.

Pins 118 are biased in an unlocked position by pin springs 124 which are held in place by pin spring retainers 138. A lower gasket 120 seals against a lower sealing ring 156 of radiator fill tube 140 during normal operation. In the event of an over pressurized condition, liquid and gas escapes by forcing lower ring 122 to move up so that the liquid and gas is released through overflow tube 142. Pins 118 make contact with a locking ring groove 148 disposed within radiator fill tube 140 preventing safety radiator cap 100 from being removed until the cooling system is no longer under pressure.

Pressure plunger 134 is biased in an un-locked condition by center spring 114 which pushes against a center housing 132 and is held in place by center spring retainer 112. As the pressure decreases, center spring 114 forces pressure plunger 134 to move downwards which allows pins 118 to retract which in turn allows safety radiator cap 100 to be removed. This embodiment requires radiator fill tube 140 to be manufactured with locking pin ring 148.

Referring now to FIGS. 5 and 6, another embodiment of the safety radiator cap is shown having a conventional radiator fill tube 300 that lacks locking pin ring 148 (FIG. 4). Pins 118 have pressure pads 152 mounted on their ends. As pins 118 are forced outward, pressure packed 152 deform against the inside surface of radiator fill tube 300. Pressure pads 152 may be made of rubber or other high friction deformable material. As the pressure increases in the cooling system, safety radiator cap will be highly resistant to movement due to the pressure of pins 118 and pressure pads 152 being forced against the inside of radiator fill tube 300. At the pressure is released, pins 118 will retract thus allowing safety radiator cap to be removed.

Now referring to FIGS. 7, 8 and 9, another embodiment of the safety radiator 200 is shown having a stationary center slide to 234 mounted on a center support to 226. In this embodiment, safety radiator 200 has a cap portion 206 held in place by an end holder 204. Of course other means are acceptable to hold cap 206 in place thus eliminating the need for end holder 204. Cap portion 206 encloses an upper ring 202 in contact with an upper gasket 208. The cooling system is sealed when lower sealing ring 222 pushes against a sealing portion of a radiator fill tube (not shown). As the pressure increases within the system lower sealing ring 222 is forced up allowing liquid and gas to escape but also forcing pins 218 outward exerting pressure against an interior wall of radiator fill tube (not shown).

Pins 218 move outward when pin followers 216 follow the angled surface of center slide 234 as lower ring 222 is forced upward due to pressure within the cooling system. Pressure pads 252 deform to apply frictional pressure making removal of safety radiator 200 difficult in an unsafe condition. Pins 218 are biased in an unlocked condition by pin springs 234 which are held in place by pin spring retainer 238. Lower ring 222 is biased to normally seal the cooling system by spring 210 which moves upward in response to the pressure within the cooling system. A center housing 232 provides support for a center pin 226 which holds center slide 234 firmly in place.

The amount of play that lower ring 222 has may be adjusted by appropriate selection of pin springs 224. As the pressure builds, lower ring 222 begins to move upward releasing some pressure through an overflow tube (not shown). As the pressure begins to build more however, lower ring 222 will be forced to move further upward applying pressure through pins 218 making removal of safety radiator cap 200 more and more difficult as the pressure increases.

Additionally, although the present invention is described in use with a radiator, it is easily adaptable for use with any pressurized application such as a hydraulic filling system, steam lines, etc. Also, some radiator systems do not have a user access cap as described above. Those systems use a pressurized overflow system that utilizes a fill cap attached to the overflow container rather than on the radiator directly. It is within the scope of this disclosure to include using the instant invention in such a system in the same way as described above with the difference being that the safety pressure cap fits within the overflow collar rather than the radiator directly.

Although the instant invention has been described in relation to particular embodiments thereof, many other variations and modifications and other uses will become apparent to those skilled in the art. 

1. A safety pressure cap comprises: a housing; a cap portion disposed on an upper end of said housing; a lower sealing portion disposed towards a lower end of said housing; a center slide centrally disposed in said housing; a pressure plunger having a sloping section; said pressure plunger being slidably constrained to move along said center slide; and at least one pin having a following end moveably disposed to move along said sloping section wherein said at least one pin moves generally perpendicular to a longitudinal axis defined by said center slide.
 2. The safety pressure cap according to claim 1 further comprising a pressure spring disposed between said cap portion and said lower sealing portion.
 3. The safety pressure cap according to claim 1 further comprising a sealing gasket disposed on a lower side of said cap portion.
 4. The safety pressure cap according to claim 3 further comprising a plunger biasing spring centrally disposed between said housing and an upper portion of said pressure plunger.
 5. The safety pressure cap according to claim 4 further comprising at least one pin biasing spring disposed between said following end and a side of said housing whereby said pin is biased against said sloping section.
 6. The safety pressure cap according to claim 5 further comprising a locking end disposed on an outside end of said pin.
 7. The safety pressure cap according to claim 6 wherein said locking end is made of rubber.
 8. The safety pressure cap according to claim 1 further comprising: a collar whereby said safety pressure cap removeably fits substantially within; at least one locking means disposed in said collar substantially aligned with said at least on pin wherein when said pin is outwardly moved, said safety pressure cap is locked in place until said pin retracts.
 9. The safety pressure cap according to claim 8 wherein said at least one locking means is an opening in said collar.
 10. The safety pressure cap according to claim 8 wherein said at least one locking means is a ridge disposed on an inner surface of said collar.
 11. A safety pressure cap comprises: a housing; a cap portion disposed on an upper end of said housing; a lower sealing portion movably disposed towards a lower end of said housing wherein said lower sealing portion moves in response to pressure; a pin slide having a sloping section fixedly disposed within said housing; and at least one pin having a following end moveably disposed to move along said sloping section wherein said at least one pin moves generally perpendicular to a longitudinal axis of said safety pressure cap.
 12. A safety pressure cap comprises: a housing; an upper sealing means for sealing said safety pressure cap; a lower sealing means for sealing said safety pressure cap against an inner collar; and a pressure retaining means for locking said safety pressure cap when under pressure.
 13. The safety pressure cap according to claim 12 wherein said upper sealing means is a gasket disposed on a lower surface of said safety pressure cap.
 14. The safety pressure cap according to claim 13 wherein said lower sealing means is a moveably disposed plug having a sealing gasket disposed on a bottom surface therein.
 15. The safety pressure cap according to claim 12 wherein said pressure retaining means comprises a pin slide centrally disposed therein and at least one pin having a pin follower on an end therein whereby said pin moves in response to pressure by moving along a sloping surface of said pin slide.
 16. The safety pressure cap according to claim 15 further comprising a locking end disposed on an opposite end of said at least one pin.
 17. The safety pressure cap according to claim 8 wherein said collar is disposed on a radiator.
 18. The safety pressure cap according to claim 8 wherein said collar is disposed on a radiator overflow.
 19. The safety pressure cap according to claim 1 further comprises a hold down portion disposed on said cap portion.
 20. The safety pressure cap according to claim 19 wherein said hold down portion is a screw tab. 